The cingulum as an important measure of individual difference in brain development

We investigated the relationship between individual differences in white matter microstructure and cognitive abilities in children. Individual differences in white matter were investigated in a representative database of typical development (NKI Rockland Sample, n=74, Age: 13.93 + 3.164SD) by extracting FA values for 10 major white matter tracts (JHU white matter atlas) and grouping individuals by similarity using a data-driven clustering approach. The algorithm indicated the presence of two groups that were distinguished primarily by FA of the left and right anterior cingulum (p<0.001). The range of FA values within the cingulum were used to group children in an independent sample with large variation in cognitive abilities (Centre for Attention, Learning, and Memory; n=165, Age: 9.81 -1.191SD). Comparison of cognitive scores between these groups indicated significant differences in fluid IQ, vocabulary, verbal and visuospatial short-term and working memory, and long-term memory (p<0.05). To investigate the association between cognitive scores and specific connections, the cingulum tract was reconstructed and connections were mapped using a connectomics approach. The results indicated significant differences between the clustering-defined groups in connections of the cuneus, parahippocampal, enthorhinal, and superior frontal cortex (p<0.05). A specific association between variation in fluid IQ and strength of the connection between the left precuneus and left superior frontal cortex was found (beta=0.286, p=0.005). These results indicate that cingulum-mediated connections are closely associated with inter-individual variation in cognitive ability in development.